Sapphire’s HD 6870 is a reference designed and clocked card, meaning the GPU runs at 900MHz and the memory at 1050MHz (4200MHz effectively). For our overclocking, we used MSI’s Afterburner v2.0, which allows for altering GPU and memory clocks, regulating fan RPM but not altering voltages in software. Thanks to Sapphire, however, HD 6800 owners can download a free overclocking tool called TriXX, which allows for meddling with GPU voltages entirely in software.

Without changing the voltage we managed to push the GPU from 900MHz to 950MHz, whereas upping the voltage to 1.299mV resulted in stable 1002MHz for the GPU.